Reference ranges for cardiovascular indices for adolescents derived using

the Ultrasonic Cardiac Output Monitor (USCOM)

Cattermole GN, Ho GYL, Mak PSK, Graham CA, Rainer TH.

July 2011

Disclosure

• Accommodation for conference provided by Pacific Medical Systems (distributors of USCOM)

USCOM

Ultrasonic cardiac output monitor

Rapid non-invasive measurement of central haemodynamic indices:

• Cardiac output (CO)• Stroke volume (SV)• Systemic vascular resistance (SVR)

Suprasternal transducer

position

Operation

Screenshot

Reference ranges• Based on unpublished data

from 500 healthy subjects in rural Australian community

• 52 aged 2-11• 32 aged 12-16

Previous work

Resuscitation 2010;81:1105-1110First presented as an abstract at ACEM 2009, Busan, Korea

Objectives

1. To derive reference ranges for heart rate (HR), cardiac output and index (CO, CI), stroke volume and index (SV, SVI) and systemic vascular resistance and index (SVR, SVRI) in Chinese adolescents in Hong Kong using USCOM.

2. To compare these ranges with those from Australia.

Subjects

4 schools

590 subjects (49% male)

Mean age (SD): 15.7 (2.1) years

MeasurementsHeight and weight Blood pressure USCOM

Centile curves

Centile curves (2.5, 10, 50, 90, 97.5)

SV

(m

l)

Age (years)

0

20

40

60

80

100

120

10 11 12 13 14 15 16 17 18 19 20

Stroke Volume

CO

(l.m

in-1

)

Age (years)

0

1

2

3

4

5

6

7

8

9

10

11

10 11 12 13 14 15 16 17 18 19 20

Cardiac Output

SV

R (

d.s

.cm

-5)

Age (years)

0

500

1000

1500

2000

2500

10 12 14 16 18 20

SVR

SV

I (m

l.m-2

)

Age (years)

20

30

40

50

60

70

80

90

10 11 12 13 14 15 16 17 18 19 20

Stroke Volume Index

CI

(l.m

in-1

.m-2

)

Age (years)

0

1

2

3

4

5

6

7

8

10 11 12 13 14 15 16 17 18 19 20

Cardiac Index

SV

RI

(d.s

.cm

-5.m

2)

Age (years)

0

1000

2000

3000

4000

10 12 14 16 18 20

SVRI

Means, ranges (+/- 2sd)12 13 14 15 16 17 18

SV, mL75.4

(45.2 – 105.6)79.6

(45.5 -113.7)81.5

(47.0 – 116.1)78.8

(42.9 – 114.8)77.3

(46.1 – 108.4)79.2

(47.7 – 110.6)80.2

(45.5 – 114.8)

SVI, mL.m-2 57.7 (38.9 – 76.6)

54.4 (33.8 – 74.9)

53.3 (32.3 – 74.4)

49.0 (28.8 – 69.2)

47.5 (26.4 – 68.6)

49.9 (30.8 – 69.0)

29.6 (49.3 – 68.9)

CO, L.min-1 6.1 (3.7 – 8.5)

6.5 (3.3 – 9.7)

6.7 (3.1 – 10.3)

6.1 (2.6 – 9.6)

5.8 (3.1 – 8.5)

6.1 (3.2 – 9.0)

5.8 (2.9 – 8.7)

CI L.min-1.m-2 4.7 (3.0 – 6.4)

4.4 (2.4 – 6.4)

4.4 (2.1 – 6.6)

3.8 (1.8 – 5.8)

3.6 (1.7 – 5.4)

3.9 (1.8 – 5.9)

3.6 (1.9 – 5.3)

SVR d.s.cm-5 1043 (560 – 1527)

1019 (536 – 1503)

1090 (447 – 1733)

1168 (412 – 1923)

1250 (597 – 1902)

1158 (476 – 1839)

1229 (613 – 1845)

SVRI d.s.cm-

5.m2

1347 (747 – 1947)

1487 (657 – 2318)

1666 (630 – 2701)

1867 (658 – 3077)

2116 (247 – 3986)

1859 (555 – 3164)

1988 (833 – 3144)

MAP, mmHg76.4

(59.0 – 93.7)77.2

(62.3 – 92.1)84.5

(64.2 – 104.8)81.3

(60.0 – 102.6)85.6

(67.0 – 104.3)82.4

(62.2 – 102.7)83.0

(62.0 – 103.9)

HR, min-1 86.0 (62.2 – 109.9)

87.7 (58.2 – 117.2)

85.4 (54.7 – 116.1)

81.0 (52.9 – 109.1)

80.0 (47.1 – 112.9)

80.7 (51.3 – 110.2)

75.2(44.9 – 105.5)

Australian Comparison

Australian (n=32)

Chinese (n=360) p

Stroke Volume Index (ml.m-2) 54

(7)52.6

(10.8) 0.37

Cardiac Index (l.min-1.m-2) 4.1

(0.5)4.2 (1.1) 0.62

SVRI(d.s.cm-5.m2)

1748(324)

1685(634) 0.10

Means (sd), t-testSubjects aged 12-16 years old

Other results

• There was poor correlation between age and cardiovascular parameters.

• SV correlated weakly with weight and height, and was significantly higher in boys than in girls.

• In the group of 12-18 year olds, parameters were normally distributed.

• Inter-observer reliability of USCOM measurements was very good.

Reference ranges

Age SVI CI SVRI(years) (ml.m-2) (l.min-1.m-2) (d.s.cm-5.m2)

1-2 31-55 3.5-6.5 750-1600

3-4 37-67 3.6-7.1 750-1700

5-11 42-76 3.3-6.9 910-2000

12-18 30-70 2.0-6.0 510-3000

Conclusion

• This is the only study to derive reference ranges for cardiovascular indices for Chinese adolescents, and the largest such study in any population.

• We hope that the use of these values will improve the diagnosis, treatment, management and monitoring of adolescent patients in emergency departments.

Thanks to…The staff and children from participating schools in Shatin